Other than a couple missed deep throws, I think EJ has looked really composed for a rookie, especially considering his pre-season.
The interception was a dumb, dumb, decision, but it wasn't like he does that a lot, so I consider it an isolated mistake... even vets do that sometimes. The fumble was a missed block, but he could use to tighten up his form so the ball is a bit higher, again another thing that isn't unique to him or even rookies.
Two games in, he's shown poise, command, decent accuracy and a solid arm. Couldn't ask for more as a rookie.